Scientific Nutrition Update 19: Caffeine

You have to love caffeine.  Has to be one of the most socially acceptable drugs of all time, and it feels fantastic.  Highly recommend it.  But today we discuss the health and mental effects of caffeine.


For today’s episode we are going to talk about one of my favorite drugs: caffeine. Now just to be clear, I will not be talking about health effects of coffee or tea that are separate from caffeine.  This is focused purely on caffeine, those other episodes will come later. So caffeine, that magical substance that gave me the focus to write my book, has carried me through all-nighters, and gives me enough focus that I don’t accidentally fall asleep during boring committee meetings.  But how much do you really know about caffeine?


First and foremost we know it feels fantastic.  I mean who among us doesn’t love that very first feeling from caffeine, the confidence, the energy, the belief that the problem you are dealing with can be solved.  It’s more than a little intoxicating. However, this feeling fades fast, because caffeine has a pretty vicious addiction and tolerance curve. Meaning you get a tolerance pretty quick, and it has pretty strong withdrawal symptoms.  However, overall I have to say caffeine seems to be an intriguing compound.


In humans caffeine is absorbed at about 99% within about 45 minutes, which seems to suggest it has pretty incredible biovailability and it is able to freely pass through the blood-brain barrier.  Caffeine is an adenosine receptor antagonist, meaning that it binds to the adenosine receptor and blocks the actions of other compounds. Now the reason this is important is because adenosine receptors seem to inhibit the release of excitatory neurotransmitters.  So basically normally the receptor keeps these excitatory neurotransmitters from being released, and caffeine helps interrupt that so that the excitatory neurotransmitters can be released. This effect seems to in part seem to contribute to increased dopamine transmission, which could help explain why caffeine feels so good, and why it is so addictive.  


One of the really cool things about caffeine is that it is a proven nootropic, meaning that it is a compound that can make you “smarter.”  Doses of less than 500 mg seem to improve information processing, though this effect is somewhat small and may primarily show up as an increase in speed.


However, it is also important to realize that caffeine can interrupt sleep.  Which when you are pulling an all-nighter is a desired effect, but when you are just using it during the day, obviously it is not desirable.  However, it seems this effect is actually more limited than many people think, and removing caffeine does not seem to help people with poor sleep.


Caffeine naps, which have become popular among the tech elite, are actually a shown way to improve performance.  All you have to do for one of the effects of this, is drink a big cup of coffee, quickly so it doesn’t start kicking in, and then take a twenty minute nap.  When you wake up, you will feel fantastic. Seriously try this one out.


There is even evidence that caffeine can improve athletic performance.  There was a small study done on ten male athletes that showed a 8.5% increase in work done in an intermittent sprint protocol.  Now there are several important notes here. One the dose of caffeine was high. 6 mg per kg which for someone who weighs 275 lbs like me would be 750 mg of caffeine or 12 shots of espresso for me…that’s a lot of caffeine.  Plus again there were only ten total subjects in this study so be very careful in analyzing it. It does however seem to also help somewhat with submaximal exercise, with an increase from 75 minutes to 90 in one study.


Now it is important to remember that very high doses of caffeine can lead to symptoms that seem to mimic generalized anxiety disorder.  Admittedly these doses were super high so like 1000 mg per day or about 16 shots of espresso. Not a normal amount, but there is a definite possibility that large amounts of caffeine can contribute to anxiety symptoms.  


Also just to be clear, there is no evidence of caffeine abuse in the same manner as abuse of other stimulant drugs such as cocaine, amphetamines, or similar.  When I say it is highly addictive I mean it in more of a colloquial sense in which many people seem to suffer withdrawal symptoms upon discontinuing use. You don’t seem to see people continuing caffeine use despite worsening physical or psychoemotional symptoms.  


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